Combined control head seal and relief valve for pressurized fluid dispensing apparatus

ABSTRACT

A movable sealing member is positioned in an annular space between the control head and the neck of the pressurized container and is spring loaded to assume a sealing position when normal pressures are present in the container. Abnormally high pressures in the container move the seal against the spring to a position wherein the interior of the container is in communication with a venting passageway.

United States Patent Hansen 1 1 Apr. 25, 1972 [54] COMBINED CONTROL HEAD SEAL 3,283,959 11/1966 Muller ..222/396 AND RELIEF VALVE FOR 3,018,914 1/1962 Webster PRESSURIZED FLUID DISPENSING 1,984,375 12/1934 Johnston ..222/3 APPARATUS Primary ExaminerRobert B. Reeves [72] Inventor: Arne Hansen, New City, NY. Assistant ExaminerFrancis J. Bartsuka [73] Assignee: Walter Kidde & Company, Inc., Belleville, Ammey Darby & Darby [57] ABSTRACT 22 F] d: I I I 6 Nov 1969 A movable sealing member is positioned in an annular space [21 Appl. No.: 873,950 between the control head and the neck of the pressurized container and is spring loaded to assume a sealing position when [52] U 5.0. 222/3 222/396 normal pressures are present in the container Abnormally [5H In'LCL Fine 7/00 high pressures in the container move the seal against the 1 s31 Fleld 0! Search 222/188 3 396 397 Spring wherein the interim 0mm is communication with a venting passageway. Meme 5 Claims, 1 Drawing Figure UNlTED STATES PATENTS 3,005,577 10/1961 Webster ..222/397 I11 2 s 1 1 s 16 1 I9 2 1 l7 2 1 511 z -u 1 IL 2 21 1 \26 10\ 1 7 l5 PATENTED APR 25 I972 INVENTOR ARNE H AN 5 E N COMBINED CONTROL HEAD SEAL AND RELIEF VALVE FOR PRESSURIZED FLUID DISPENSING APPARATUS BACKGROUND OF THE INVENTION The present invention relates to fluid medium dispensing apparatus, and, more particularly, to such apparatus which includes a control head secured to the neck of a pressurized container for controlling the flow of fluid medium from the container.

In apparatus of this type, such as fire extinguishers, it is common practice to provide a pressurerelief valve in the control head. This relief valve is conventionally positioned in a bore extending through the control head and therefore creates a potential gas leakage point which is in addition to the potential leakage points existing at the seal between the control head and the pressurized container and at the outlet valve.

SUMMARY Accordingly, it is an object of the present invention to provide apparatus of this type in which a relief valve is incorporated without adding a potential point of leakage.

Another object is to provide a combined control head seal and relief valve for such apparatus.

The foregoing objects are accomplished by providing in fluid medium dispensing apparatus an annular space between the control head and the neck of the pressure vessel, an annular sealing member in the annular space movable in response to pressure between a sealing position and a venting position, and a spring member for holding the sealing member in the sealing position when the pressure in the container is below a predetermined value.

BRIEF DESCRIPTION OF THE DRAWING A preferred embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawing, forming a part of the specification, wherein:

The single FIGURE of the drawings is a sectional view of fluid medium dispensing apparatus incorporating a combined control head seal and relief valve in accordance with the 1 present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing in detail, there is shown fluid dispensing apparatus which includes a pressure container having a neck 11, a control head 12 extending into the neck 11, a valve 14 carried by the control head, and a combined control head seal and pressure relief valve according to the present invention.

The neck 11 of the container has a thick lower section 15, a thin upper section 16 having a larger inner .diameter than the lower section, and a conical intermediate section 17 provided with a vent hole 19.

The control head 12 is of stepped cylindrical construction having the largest diameter portion 20 at the bottom within the lower section of the neck 11. The next higher portion 21 is of substantially smaller diameter and providesan annular space 22 between the control head and the neck 11. Above this is a portion 24 of slightly smaller diameter. The top control head portion 25 is of the smallest diameter and is positioned above the neck.

An annular sealing member 26 is positioned within the annular space 22. Above the sealing member a stepped seal backup member 27 is slidably mounted on the control head. The backup member includes a lower large diameter section 28 dimensioned to receive the control head portion 21 and an upper smaller diameter section 29dimensioned to receive the control head portion 24. A coil spring 30 encircles the control head portion 24 and engages the upper surface of the section 28 of the back-up member. An' L-shaped annular spring retainer 31 is mounted on the control head portion 24 and engages the upper end of the spring 30. One arm 32 of the retainer extends laterally over the upper end of the neck section 16.

An annular nut 34 is threaded onto the neck 11 and engages the shoulder formed at the junction of the control head portions 24 and 25 to hold the control head within the neck. The nut 34 also engages the lateral arm 32 of the retainer to vertically position the control head with respect to the neck 11. A split ring 35 is mounted in an annular groove provided in the control head portion 24 to maintain the retainer 31 and the spring 30 in position when the unit is disassembled.

In operation, when the unit is pressurized to its normal operating pressure, the spring 30 forces the back-up member 27 downwardly until it engages the shoulder formed by the junction of the control head portions 21 and 24. In this position, the seal member 26 engages the inner surface of the neck section 15 and the surface of the control head portion 21 to provide a pressure seal therebetween.

If the pressure within the container increases to a dangerously high value (for example, due to heating of the container or over charging), the pressure within the container pushes the sealing member 26 and the back-up member 27 upwardly compressing the spring 30.

When the pressure reaches a predetermined value, the sealing member 26 is moved by the pressure into the zone adjacent the conical neck section 17. As a result, the seal between the neck and the control head is broken and fluid flows from the container past the sealing member 26 and through the vent hole 19 to relieve the excess pressure. After sufficient fluid has been vented to reduce the pressure below the predetermined value, the sealing member 26 is moved downwardly by the spring 30 to once again provide a seal between the control head and the neck.

It will be seen from the foregoing that the present invention provides fluid dispensing apparatus which includes a combined control head seal and relief valve so as to incorporate a relief valve without adding a potential point of leakage.

Iclaim:

1. In a fluid medium dispensing apparatus including a container for storing a fluid medium under pressure, said container having a neck member, a control head member secured to the neck of said container, said control head member including valve means in communication with the fluid medium serving as an outlet for the fluid medium, said control head member and said neck member being sized so that opposing surfaces thereof provide an annular space therebetween having a first portion of a first diameter and a second portion of larger diameter than said first portion, said members also formed with a space therebetween to provide a fluid flow passage between said container interior and said annular space and a seating surface on one of said members adjacent said passage, venting means formed in one of said members and communicating with said larger diameter portion of said annular space, sealing means located in said annular space and in communication through said passage with the fluid medium in said container, means for holding said sealing means in a first position in said first portion of the annular space against said seatingsurface to seal off the passage and thereby seal off the venting means from the fluid medium in said container when the pressure of the medium in the container is below a predetermined value, said sealing means being moved into the second and larger diameter portion of the annular space against the force applied by the holding means to provide fluid flow communication between the interior of the container and the venting means when the pressure of the medium in the between the inner wall of the neck and the outer wall of the control head with at least one of said control head and neck members being of stepped form to provide said annular space with said first and second portions. 

1. In a fluid medium dispensing apparatus including a container for storing a fluid medium under pressure, said container having a neck member, a control head member secured to the neck of said container, said control head member including valve means in communication with the fluid medium serving as an outlet for the fluid medium, said control head member and said neck member being sized so that opposing surfaces thereof provide an annular space therebetween having a first portion of a first diameter and a second portion of larger diameter than said first portion, said members also formed with a space therebetween to provide a fluid flow passage between said container interior and said annular space and a seating surface on one of said members adjacent said passage, venting means formed in one of said members and communicating with said larger diameter portion of said annular space, sealing means located in said annular space and in communication through said passage with the fluid medium in said container, means for holding said sealing means in a first position in said first portion of the annular space against said seating surface to seal off the passage and thereby seal off the venting means from the fluid medium in said container when the pressure of the medium in the container is below a predetermined value, said sealing means being moved into the second and larger diameter portion of the annular space against the force applied by the holdiNg means to provide fluid flow communication between the interior of the container and the venting means when the pressure of the medium in the container exceeds said predetermined value to vent the medium.
 2. Apparatus as in claim 1, wherein said holding means comprises a spring.
 3. Apparatus according to claim 2, including an annular back-up member between said sealing element and said spring, and means for limiting the movement of said back-up member under the influence of said spring means.
 4. Apparatus according to claim 1, including means on one of said members for retaining said sealing element in said annular space when said container is not pressurized.
 5. Apparatus as in claim 1, wherein said control head member fits within said neck, the annular space being formed between the inner wall of the neck and the outer wall of the control head with at least one of said control head and neck members being of stepped form to provide said annular space with said first and second portions. 